As the amount of available information increases, efficient and accurate methods of retrieving information are increasingly important. While many approaches to searching through sets of documents have been advanced, such approaches are typically based directly on content of the documents. One common approach is to execute a search query based on one or more terms and to return a list of documents that contain terms from the search query. However, these approaches are of limited utility because they may contain documents that are irrelevant to the query and/or they may fail to include documents that would be useful to the user but do not match the specific search query provided by the user. Additionally, conventional methods of information retrieval fail to provide a simple method of retrieving documents that are similar to a particularly relevant document identified by the user.